<%@ page pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
String url = basePath+request.getParameter("url");
%>
<script type="text/javascript">
  window.open('<%=url%>','mywindow');
</script> 